100 THK ENTOJIOLOGIST's RECORD. 



and Y-sbaped hairs, which regularly alternate along the rows. In the 

 Banainac proper, represented by the genus Jtuna, the transparency is 

 chiefly due to the great diminution in the number of the scales, and 

 those which remain are neither much reduced in size nor altered in 

 shape. In the Pierinae, represented in this group by only a single 

 species, Diwiorphia oriw, the scales are greatly reduced in size, but are 

 neither greatly altered in shape nor diminished in numbers. 



Hence, in these three sub-families of butterflies, transparency is 

 attained in three different ways, viz. (1) by reduction in size and 

 simplification in shape ; (2) by reduction in number ; and (3) by 

 reduction in size alone. 



When we examine the moths which fall into the group, we find a 

 much greater difference in the methods, corresponding to the wider 

 divergence in affinity. In the several species of the genus Castnia the 

 scales lose their pigment, although undiminished in size, while they 

 are at the same time set vertically upon the wing, so that light can 

 freely pass between their rows. In the widely separated genus flj/elosia 

 the arrangement is nearly the same, except that the vertical scales are 

 much attenuated. In the genus Anthonn/za, which furnishes the group 

 with many species, the scales retain the normal size, shape, and over- 

 lap, but become so completely transparent that the light freely passes 

 through them. 



In all the numerous constituents of this large group of Lepidoptera 

 a very close resemblance has been produced by entirely different 

 methods ; a result which, it has been argued above, is only consistent 

 with the view that natural selection alone, among all the explanations 

 which have been suggested, has been the cause of the observed 

 phenomena. 



I owe to the kindness of Mr. Godman and Mr. Salvin the oppor- 

 tunity of studying all the butterflies of this large transparent-winged 

 group, while Mr. Herbert Druce kindly lent me those moths which are 

 not represented in the Hope Collection in the Oxford University 

 Museum. 



The Butterflies of the Chatham District. 



By J. J. WALKER, F.L.S.. F.E.S. 



Out of the 68 species recognised as British in the most recent work 

 on the subject, by Mr. J. W. Tutt, F.E.S. , no fewer than 54, or 79 per 

 cent, of the whole number, have been taken within six miles of the 

 L.C. and D.R. station at Chatham. During the last forty years, five of 

 our most beautiful and interesting species have been almost entirely ex- 

 terminated ; but even now an energetic collector may reasonably expect 

 to meet with 40 species within this area in a single fairly good season. 



The 54 species of butterflies which have been recorded from this 

 district may be classified as follows : — A — Generally distrhsuted and 

 COMMON IN MOST YEARS — 21 species : — Patiijihila ni/lramis, T/n/ineliciis 

 titauwas, CJnijfiopJiaum 2}Jdaeas, Polyommatus icarus, P. astrarclic, Callo- 

 phii/s luhi, Pii'iis Irassicaf, ]'. rapae, P. najd, FaicIiIo'c cardannncs, 

 (j<ini']iti'njx rhamni, Brentlds citjdtrosi/ne, Vanessa io, Az/lais iirticae, 

 rjjriwuds atalanta, Paran/e egeria, P. wcfjaera, Epinephch' ianira, E. 

 titliuims, Enodia hyperantlniSy Coi>v<my))ijdta paDiphilin^. B — Common in 



SOME YEARS, BUT UNCERTAIN IN APPEARANCE 3 SpecieS I Colias Illjale, 



